<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>

<div id="app">
  <h2>当前计数：{{counter}}</h2>
  <!-- <button v-on:click="counter++">+</button>
  <button v-on:click="counter--">-</button> -->
  <button v-on:click="add">+</button>
  <button v-on:click="sub">-</button>
</div>
  
<script src="../js/vue.js"></script>
<script>
  //语法糖：简写
  //proxy代理
  const obj = {
    counter: 0,
    message: 'abc'
  }

  const app = new Vue({
    el: '#app',//用于挂载要管理的元素
    data: obj,
    methods: {
      add: function() {
        console.log('add被执行')
        this.counter++
      },
      sub: function() {
        console.log('sub被执行')
        this.counter--
      }
    },
    beforeCreate: function () {

    },
    created: function() {
      console.log('created')
    },
    mounted: function() {
      console.log('mounted')
    }
  })
</script>

</body>
</html>